O2-independent formation of the inactive states of NiFe hydrogenase

We studied the mechanism of aerobic inactivation of Desulfovibrio fructosovorans nickel-iron (NiFe) hydrogenase by quantitatively examining the results of electrochemistry, EPR and FTIR experiments. They suggest that, contrary to the commonly accepted mechanism, the attacking O-2 is not incorporated as an active site ligand but, rather, acts as an electron acceptor. Our findings offer new ways toward the understanding of O-2 inactivation and O-2 tolerance in NiFe hydrogenases.